Hi guys,
Ok so I am bent on staying with LTR setup before we get deep into this. I want the 'stock' looking engine since I take her to shows and what not, I just would like a little more power. I am willing to put in about $5,000 give or take a few hundred.

So here is what I am 99% sure I am going with....
SDPC 360HP Vortech TPI engine found here http://www.sdpc2000.com/catalog/157...trip-Engine.htm[/URL]

Now I have a decently setup suspension as in signature just to get me started. I am probably gonna go with Arizona-speed and marine LTR's, only question is should I go with the semi-siamesed? Remember I want it to look stock. Other question on this issue is what year runners do I get? The engine comes with the lower vortec head intake on it, is it the 85-88 or the 89+ runners or does it even matter with chip tuning?

Where can I get new injectors and what size/brand should I go with?
What size TB should I run, they suggest a 52mm but I was just wondering what brand etc...
I am getting a custom chip burnt for this engine as well so the computer issue will not be a problem.
I have a friend that can weld for me so hopefullythe EGR pipe will not be an issue.
I have no Exhaust upgrades from factory yet, what do you recommend from Headers all the way back, brands etc... I was thinking Hooker headers, some sort of high-flow cat, and Hooker Cat-back.

On a side note with all this installed and running correctly what do you think she will run with good tires? I was hoping for mid 13's when it is all said and done.

Please help me decide on these issues before I make purchases!!

 

I don't think that engine comes with a plenum. If thats the case, then the runners, throttle body, and plenum all need to match. Meaning all need to be 85 to 88, or all of them 89 to 92. If you previously had an 86 setup in there, then I would just go with an 85 to 88 set of runners, plenum, and tb. The reason is that I think the way the throttle cable attaches to the throttle body changed in 89. This way, you already have your cable. If you come across a good deal on 89 and up parts, just go ahead and get it, since a throttle cable is only like $10 or $15.

The semi-siamesed runners will breath better up top, but won't look stock. You need to decide where you draw the line on compromises like this.

You can get a 52mm throttle body if you want, but honestly its a waste of money. You don't need it, the stock 48mm flows alot more than the rest of your setup. There are guys running low 12s on the stock 48. I have a 52 only cause it was free, long story...

Best deal on injectors (if they still sell them) are SLP's 25 lb injectors. They are take offs from LS1 Camaros. They have about 5 to 10 miles of use on them. They sell for about $90 or so.

Properly tuned, and with some suspension work, you should see low 13s I would think.

 

Thanks for the help, I am gonna look into those injectors prices right now. As for the runners and plenum I think I will stay 85-88 I will just have to make sure they send me the right lower intake I guess, are they different? Anyone else want to chime in? Thanks guys I just have to get this straightened out before the car is apart....

 

double post SORRY.....

 

well if you are going to put in a vortec headed motor you can't reuse your stock lower intake manifold. you have to get the SDPC Vortec tpi manifold. that manifold is essentially the same design as an accel, tpis, or edelbrock manifold except it fits the vortec heads. that being said you could run the 89-92 runners if you want but you would have to do the cold start injector delete. another question is are you sticking with MAF or going to SD? I feel the 360HP were prob. achieved using SD as the MAF unit will restrict airflow. if you switched to SD you could get the newer year runners as the 730 ecm has the cold start injector deleted in its programming. as for the LS1 injectors you will need and adj. fuel pressure reg. they only flow 22 lb/hr at stock tpi fuel pressure. have to bump up pressure to 58psi to get them to flow 25. there are ls1 injectors out there that flow 28.5 lb/hr @ 58 psi which is about 24.5 at stock tpi fuel pressure. I have those on my car, got them off ebay for like $100 brand new. to use these injectors you will also prob have to grind down the fuel rail mounts as the ls1 units are shorter than stock, that is if the vortec manifold is anyhting like my accel manifold. last but not least you will prob need a bigger fuel pump to run at those higher fuel pressures as the stock unit won't push much past 50 psi. hope this helps.

edit: I now see you have an AFPR

 

I believe that engine already comes with the manifold correct? If thats the case, then you don't have much to worry about. I think you can use any year runners You don't need to grind the fuel rail mounts to use those injectors. You don't have to get an AFPR either, but it wouldn't be a bad investment. You don't have to run those injectors over 50 psi either. You can leave your pressure stock, and they will flow 25 lbs. I do however recomment a Walbro 255 in tank fuel pump.

I am partial to a SD setup, but you can stay with either MAF or SD. I don't see a problem with running either setup. I am relatively sure that the stock screened MAF will still outflow what your engine will consume.

 

hate to tell you but that is just not true. ls1 injectors are rated at 5 bar which is 58 psi do a search. this means when you run them at 43.5 psi you will only get 22 lb/hr out of them. I know this because I am running ls1 injector and have done the prom tunning to correct for them. also I merely mention the fuel rail mounts as I know first hand the injectors are shorter then stock. so in order to install them and have them seat properly I had to grind down the mounts. as far as I know the vortec manifold is based off the the aftermarket manifolds so the mounts are prob similar and may require some griding. again search about ls1 injectors and superram manifold you will see what I am talking about.

 

I have been reading into them as I was looking to replace my 24 lb LT1s which are in questionable condition with a set of LS1 injectors that I have.

I agree with that statement.

Since he is going to be needing a custom chip anyway, its no big deal if he has ~25 lb injectors. They will just change the injector constant for him.


This is contrary to your previous statement. It won't be at 22 lbs per hour, but ~25. They are a little over 28 lbs at 58 psi. They are 25 lbs when you bring them down to 43.5 psi.

I'm attaching a chart I have with injector sizes and you pressure changes their flow rate. Disregard the other things. While there is no entry for 28 lb injectors, you can still get general idea of where the flow rate would fall.

 

Ugghhhh... I tried making the chart smaller, but its still too big to upload. Anyway, to illustrate my point.... there is no entry for a 28 lb or 25 lb injector in the chart. There is however a 24 lb entry. An injector rated at 24 lbs is at 43.5 psi. If you raise it to 58 psi, it would be at roughly 27 lbs.

LS1 injectors are rated 28 lbs at 58 psi. At 43.5, it works out to 25.

As far as having to grind the fuel rail mounts, I have read many threads where people have done that, and I still don't see why. I have 24 lb Lt1s installed right now. They are slightly smaller than stock TPI injectors. IF you remove the injector clips, the and install the fuel rails, the injector slides up and down a whole lot. Enough that it couldn't possibly seal properly if it is either too high up or too down. If I install the clips, they don't reach all the way down in the injector bung, but it will seat and it will seal properly.

The LS1 injectors are maybe 1/16 shorter than the LT1s. Whats important is not the overall injector size, but the distance from one o ring to the other o ring. I don't see any reason why you can't use them without grinding the rail mounts if you use the injector clips. I am going to try the LS1s as soon as I get my block back from the machine shop.

Here is a pic of a 22 lb TPI injector, a 24 lb LT1 injector, and a 25 lb LS1 injector.

 

I guess I should be a bit more clear in which injectors I was refering to. yes the 28.5 lb/hr units will flow 24.5 lb/hr at stock pressure. the 22 lb/hr I was refering to initially was if you buy the 25lb/hr ls1 units that SLP sells. to get the 28.5 units you will have to purchase them else where. as for the griding when I put them I could still see the o-ring sticking out of the rail. I did not care for that as it might be possible to push fuel past the rail. the original injector clips won't fit and ls1 injector groove doesn't go all the way around as the stock injectors did. you can slide them up but then the injector is not fully in the manifold so you may not get the best spray pattern possible this is why I chose to take about an 1/8" off the rail mounts to better fit. to show this here is a pic of them installed before I ground down the mounts.

 

The LS1 injectors are rated at 4 bars, not 5, as stated above. 4 bars is 58psi. L98 and LT1 injectors are rated at 3 bars or 43.5psi. Obviously, GM is using 1 bar to be equal to 14.5psi.

Also, the LS1 injectors are exactly 0.10" shorter from o-ring to o-ring. So, I would strongly recommend that the fuel rail mounting posts be ground down 0.10" or risk a huge fire and destroying your car.

There are two fuel rated LS1 injectors, 26.4 and 28.4#/hr. It is my understanding that the SLP injectors that are for sale are the 28.4#/hr. So, just a helpful warning to those who might buy LS1 injectors off of Ebay or some other place, be careful of which model year the LS1 injectors are out of. If you got hold of the 26.4 LS1 injectors, they would flow 22.9 #/hr at 43.5psi, as opposed to 24.6#/hr.

BTW: I would go with the 52mm TB as recommended to you.

 

So other than the fuel injector lesson that I just got taught, anyone else have opinions. I am still guessing that any injector 22# + will do? Since the chip will be custom burnt.

I also plan to stay with MAF since it's already on the car, and yes I do have an AFPR currently on the car so thats not a problem.

So what I am guessing is that unless I get Stock L98 injectors that the fuel rail will need some sort of modification?

Another question too, since the engine already comes with the intake manifold, can I choose which runner years I would like or are there different intake manifolds for the different runner years? Or would I have to specifiy to Sdpc that I would need like 85-88 runners?

 

What these guys are trying to point out isn't for every injector thats not stock, its just for certain injectors that are shorter. If you were to buy a set of Accel injectors, they are the same height as your stock L98 injectors. The modification they were talking about isn't to the fuel rail itself, but the four posts on the manifold that the fuel rail bolts onto.

I would go with a 24 or 25 lb injector for your application. I have an almost new set of Accel 26s that I am selling, PM me if you are interested. I do think that the 26s will probably be a little on the big side though.

Are you going to keep the cold start injector? I'm not 100% sure, but I think you can use any year runners with that base. Then you just need a matching plenum for the runners, and a matching tb for the plenum. All of those three are compatible within 85-88, and within 89-92.

 

I guess I plan on keeping the coldstart injector because I already have the plenum for it. Now when I go to buy injectors since usually they come in sets of 8 will I have to buy 1 more injector or 2 more for the 9th injector? Is there another injector or two more because of cold-start? Can I reuse my 19# cold start injector with chip work?

 

I do believe that you can keep your original cold start injector. if memory serves me the 305 and the 350 had the same cold start injector(don't hold me to that). if you put in bigger regular injectors and change the prom to match the ecm will control how much fuel to dump in to keep it the necessary air/fuel ratio. if the car is warm or it really isn't cold out I don't believe the cold start even fires to start the car. it only fires when it needs an extra kick. the difference in that extra fuel needed to start your 305 and the amount to start that 350 should be minimal. if you buy new injectors you will just be getting 8.

 

thanks 1992rs/ss, so what your saying is I can keep the 9th injector from my 305 tpi? Thats what i was hoping I could get away with. thanks!